A recent study assessed the incidence of thrombotic events occurring in patients being treated with ibrutinib for a hematologic malignancy.

The findings, which were published in the British Journal of Haematology, may help in considering how ibrutinib changes the risk-benefit ratio of ongoing anticoagulation (AC) and/or anti-platelet agents, the study authors wrote.

Ibrutinib, an irreversible Bruton tyrosine kinase inhibitor, is used to treat several B-cell malignancies. Because this population is more likely to be at a higher risk for thrombotic events, it is important to understand the incidence of thrombosis in patients taking ibrutinib, according to the authors. 

For the study, the authors conducted a single-institution retrospective cohort analysis of patients taking ibrutinib. The study included 565 patients: 73.6% had chronic lymphocytic leukemia (CLL) and 81% were treated through a clinical trial. Prior to treatment with ibrutinib, 13.8% had a history of 99 venous thrombosis (VTE) episodes.

Additionally, at any time, 39.6% of patients received anti-platelet agents and 8.3% received AC concurrently with ibrutinib. Median overlap of anticoagulation and ibrutinib was 59.5 days, according to the study.

The results showed that 3.9% of patients experienced 24 acute thrombotic events during ibrutinib treatment. After starting ibrutinib, VTE developed at a median of 7.5 months and arterial thrombosis developed at a median of 24.6 months.

Of the VTEs, 87.5% were deep vein thrombosis (DVT). DVT was largely associated with having a central line, immobilization, and hospitalization. Of the 16 arterial thrombosis events, the majority were acute cerebrovascular accidents, with AF potentially contributing to 4 events.

According to the analysis, age and prior venous or arterial thrombosis was shown to be associated with increased risk for VTE during ibrutinib treatment. Arterial thrombosis was associated with longer duration of malignancy and age.

There was significantly more bleeding complication than recurrent thrombosis following a thrombotic event, despite the short median duration of AC.

“The majority wo developed a thrombosis while on ibrutinib started on anti-platelet agents and/or AC, but many experienced bleeding events and recurrent thrombosis was rare,” the authors wrote.

Overall, the authors concluded that in patients treated with ibrutinib, the data showed that the rate of thrombosis was low and the cumulative incidence of VTE was lower than expected. Many patients in the study received concomitant antiplatelet agents, which may have reduced this risk, despite the short overlap.

References

Kander EM, Zhao Q, Bhat SA, et al. Venous and arterial thrombosis in patients with haematological malignancy during treatment with ibrutinib. British Journal of Haematology. 2019. https://doi.org/10.1111/bjh.16209